Users who moved away from Microsoft products (to Firefox and RealPlayer) in an effort to avoid security problems are facing high risk vulnerabilities this week. Even Mac users needto install a security patch this week. Not to be out done, users of Internet Explorer also have a critical new vulnerability to contend with. See #1, #2, #4, and #3 below. Also, because working exploit code is now circulating, Microsoft Exchange users and Oracle users should install patches on a priority basis if they haven't already. (#6 and #7 below)
Alan
@RISK is the SANS community's consensus bulletin summarizing the most important vulnerabilities and exploits identified during the past week and providing guidance on appropriate actions to protect your systems (PART I). It also includes a comprehensive list of all new vulnerabilities discovered in the past week (PART II).
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Part I is compiled by Rohit Dhamankar (rohitd_at_tippingpoint.com) at TippingPoint, a division of 3Com, as a by-product of that company's continuous effort to ensure that its intrusion prevention products effectively block exploits using known vulnerabilities. TippingPoint's analysis is complemented by input from a council of security managers from twelve large organizations who confidentially share with SANS the specific actions they have taken to protect their systems. A detailed description of the process may be found at http://www.sans.org/newsletters/cva/#process
Description: Mozilla Firefox has been steadily gaining market share among browsers. The Firefox browser contains multiple flaws that can be exploited to execute arbitrary code with the privileges of the logged-on user. The following are three of the more severe flaws: (a) The "<link>" tag can be used to load a custom image as a site's icon in Firefox. However, Firefox does not sufficiently validate the source for the custom image. Hence, by using "javascript:" URL as the image source, it is possible to execute arbitrary commands on the client. A proof-of-concept exploit has been posted. Note that visiting a malicious web page is sufficient to leverage this flaw. (b) The "<embed>" tag's "pluginspage" attribute is used to load the URL for installing a plug-in. By using a "javascript:" URL, it is possible to execute arbitrary commands on the client. (c) A malicious webpage can open privileged pages such as about:config in the sidebar, and then use javascript URLs to execute arbitrary code on a user's system.
Status: Mozilla confirmed. Firefox version 1.0.3 has been released. This version fixes many other security vulnerabilities.
Council Site Actions: Just a handful of sites officially support or use Firefox. One site has already patched, as they received notification over the weekend. The other sites have advised their users to patch.
Description: RealPlayer, a very popular cross-platform media player, contains a buffer overflow in processing Real Media (".ram") files. A ".ram" file specifies the URL where media clips are stored. The buffer overflow occurs because RealPlayer does not check the length of the hostname specified in a media clip's URL. As a result, a .ram file containing the following entry " http://<long hostname>/example.ram" will lead to the buffer overflow. The flaw can be exploited to execute arbitrary code on the client system with the privileges of the logged-on user. Since many browsers automatically open a ".ram" file with realplayer, the flaw may be leveraged without any user interaction.
Status: RealPlayer has issued updates for all platforms. Users should be advised to upgrade their player by clicking "Tools" or "Help" menu and then choosing "Check For Updates".
Council Site Actions: This software is not officially supported at any of the council sites. However, a few of the sites plan to notify their users.
Description: Windows Explorer reportedly contains a flaw that can be exploited to execute arbitrary script code on a Windows client. Windows Explorer, in its default configuration, displays information about some types of files, such as the author's name, attributes, etc., in the preview pane when the file is selected. If the author's name resembles an email address, the name is transformed into a "mailto:" link for display. A problem arises because the author's name is not sufficiently sanitized for shell meta-characters. A specially crafted author's name in certain files can lead to execution of script code when the file is selected. Note that it is not necessary to open the file; pre-viewing the file is sufficient to leverage the flaw. An attacker can construct a malicious file in a shared network folder, and entice a victim via e-mail or webpage to browse his shared folder. Proof-of-concept Word documents have been posted.
Status: Microsoft has not confirmed, no updates available. A suggested workaround is to choose the "Windows Classic Folders" view under "Tools->Folder Options" in any Explorer window. Block the ports 139/tcp and 445/tcp to prevent the attacks originating from the Internet.
Council Site Actions: All of the reporting council sites are waiting for a patch from the vendor. Several have commented that they are already blocking the affected ports (139 and 445) at their network security perimeter. One site commented they will rely on the Cisco security agent software to prevent execution of the Trojan code.
Description: Apple has released a cumulative security update for Mac OS X on April 15, 2005. This update fixes a vulnerability in Safari browser that can be potentially exploited to execute arbitrary JavaScript code with the privileges of the logged-on user. The problem arises due to a flaw in the "XMLHttpRequest" object that allows an attacker to read arbitrary files present on the client system. The other problems fixed by this update can be exploited only by local attackers.
Status: Apply the fixes referenced in the Apple Advisory 301327.
Council Site Actions: Four of the reporting council sites are using the affected software. All plan to patch during their next regularly schedule system update process.
Description: xv is an image manipulation program for UNIX systems that can handle a large number of image formats such as gif, jpeg, tiff etc. The program ships by default with many Linux distributions, and can be configured as a default image viewer for web browsers. The program contains a buffer overflow in the Planetary Data System (PDS) image decoding routine, format string vulnerabilities in handling tiff and PDS image formats, and remote command execution flaw due to insufficient checking of shell meta-characters in filenames. A malicious image (in a webpage or email) may exploit these flaws to execute arbitrary code on the client system. The technical details required to exploit these flaws can be obtained by comparing the fixed and the vulnerable versions of the source code.
Status: Gentoo confirmed, fixes available.
Council Site Actions: Two of the reporting council sites are using the affected software. The first site does not officially support the software and has notified their users. The other site has a large number of systems on which xv can be executed, either from a local installation or from a shared network file system. As far as they know, no significant number of systems have a web-browser configuration in which xv is automatically invoked. Therefore, it is relatively unlikely that malicious images will be viewed using xv. They plan to update to a newer xv version this summer.
Description: Exploit code and technical details have been posted for the "CRITICAL" buffer overflow flaw in the Exchange server reported last week. Exchange servers running on Windows 2000 platforms should be patched immediately.
Council Site Updates: Most of the council sites have already patched their systems or are in the process of patching their systems. A few sites are still investigating and evaluating their risk.
Description: Multiple proof-of-concept exploits and technical details have been released for the SQL injection vulnerabilities in Oracle products. Internet facing web servers using Oracle as the back-end database should apply the patches on a priority basis.
Council Site Updates: Some of the council sites are still regression testing the patch and a few others are still investigating with their DBA teams and/or Oracle. One site is re-evaluating their remediation plan based on exploit code being released. Another site said they may be making use of the available code to verify that the updates are installed effectively at their site.
Description: Exploit code for the denial of service in Windows related to the processing of IP Options has been posted. This DoS will result in a "blue screen on death". An exploit for the TCP reset/degradation vulnerability (which affects multiple vendors including Cisco and Juniper) has also been posted. Note that some users have posted problems encountered after installing MS05-019 patch.
Council Site Updates: All council sites have already patched their systems or are in the process of patching their systems. One site mentioned they plan to use the available exploit code to verify that the patches have been installed, on systems where an installation problem is suspected.
Description: Sun has confirmed and released patches for the LDAP buffer overflow in Sun ONE/Java System Directory Server discussed in the @RISK newsletter posted on January 13, 2005.
Council Site Updates: The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
This list is compiled by Qualys (www.qualys.com ) as part of that company's ongoing effort to ensure its vulnerability management web service tests for all known vulnerabilities that can be scanned. As of this week Qualys scans for 4237 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
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